Using Receive Payment without any invoice = Negative AR. People gave you money and you never showed Why.
You are missing Invoices, if AR is negative for a name. Either Refund their money, or show there is a Sale to which it is applied.
Stop making Credit Memos; that is More Negative AR.
If you have Overdue Invoices, that is Positive AR.
Do this: Run the Reports menu > Customers & Receivables, AR Aging Summary. Customize. Filter on Amount <=0. Here are Negative AR customers, which means they sent money and no one processed it using a Sales receipt, and there was no invoice. You are missing Invoices for them.
